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Courtesy of Paul Bentzen
Evolution Impacts Environment, Study Finds
For a long time, scientists have known that how living things interact with their environment – ecology – has an impact on their evolution. Now, scientists have found that evolution has an impact on ecology too.
A team of scientists studying small fish called guppies has discovered that the streams where the guppies live change as the fish evolve.
They compared two streams on the island of Trinidad to figure out how guppies that have evolved different adaptations affect their environment. The streams they looked at were very different. One stream was home to many types of fish, some of which ate guppies. The other stream was home to only a few types of fish, none of which ate guppies.
To study the guppies’ affect on streams without other influences from the ecosystem, the scientists built artificial streams alongside the two real streams. They found that, after four weeks, guppies from the two streams had very different impacts on their ecosystems.
Guppies from the stream with many types of fish ate more insect larvae, while guppies from the other stream ate more algae. The guppies were the same species, but had adapted to eat different foods. Their different eating habits had an impact on their ecosystems. The stream with guppies eating insect larvae had more algae in it and fewer larvae than the other stream.
The difference in the guppies’ diets had other effects too. It caused a difference in how nutrients like nitrogen and phosphorus were used in the ecosystems, a difference in plants and oxygen, and a difference in the amount of organic material. Now the scientists are going to try to figure out how these sorts of changes to ecosystems affect how guppies adapt.
